[rollei_list] Re: What is Velox? What are lantern slides?
- From: Richard Knoppow <dickburk@xxxxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Mon, 21 Aug 2006 03:01:11 -0700 (GMT-07:00)
-----Original Message-----
>From: Don Williams <dwilli10@xxxxxxxxxxxxx>
>Sent: Aug 20, 2006 7:21 PM
>To: rollei_list@xxxxxxxxxxxxx
>Subject: [rollei_list] Re: What is Velox? What are lantern slides?
>
>At 05:42 PM 8/20/2006 -0700, Dick wrote:
>>I do remember the Flexichrome process. It was apparently often used
>>for advertising illustration since colors could be changed or varied
>>at will. Like photo-oil coloring Flexichrome reqired considerable
>>artistic skill to really look good.
>> For those not familiar with it Flexichrome was a variation of the
>> processes that vary the hardness of a gelatin layer with exposure.
>> The material was similar to the matrix material for dye transfer.
>> After development in a tanning developer the variable hardness of
>> the gelatin would control the uptake of dyes applied to the surface
>> with a brush. While the saturation of the color was automatic the
>> placement and choice of color was not. Reproducing something like a
>> print cloth pattern required a lot of detailed hand work.
>> Flexichrome is another victim of digital image manipulation
>> although digital probably requires at least as much work and skill.
>> I got interested in Flexichome (and dye transfer) when I was in
>> high school but never had the money to pursue it.
>> BTW, Velox was also used as a term for a print made from a
>> screened negative used in making printing plates. I don't know the
>> derivation of the term but perhaps it was from the use of high
>> contrast Velox paper to make the prints.
>
>Sounds a little like what I think was called the Kodak dye-transfer
>process. I remember helping the brother of a friend do that around 1949.
>
>Seems to me that 3 matrices were made, one for each color, all
>carefully aligned with a punch, and then each was used in turn to add
>a color to a special paper. Either the thickness or hardness of the
>gel, plus the soak time in the dye, controlled the density of each color.
>
>I think that at the time this was the best color process one could
>use for making prints at home, but it did require a lot of care and skill.
>
>Could be that I am a bit out of date and that process is still in use.
>
>DAW
>
>
>>---
>>Richard Knoppow
>>Los Angeles, CA, USA
>>dickburk@xxxxxxxxxxxxx
>>---
>
>
>Don Williams
>La Jolla, CA
>
The flexichrome matrix material was similar to dye transfer in that it
depended on differentially hardened gelatin. Somewhere I still have a
Flexichrome handbook. I don't remember if the gelatin was washed off to a
reliefe image as it is for dye transfer.
The Kodak Dye Transfer method was an improved version of an older process
called Eastman Wash-off Relief and that was bought from some independant
company, the name escapes me. Dye transfer used sheets of unhardened emulsion
coated on a support. After exposure the material was developed in a tanning
developer. Again, I don't remember the details of the formula. After
development and fixing the emulsion was washed in warm water which removed the
gelatin in proportion to the exposure, that is, the exposed parts were harder.
The matrix was then soaked in a dye solution and squeegeed off. It was then
placed in contact with the receiving paper and allowed to remain for a time.
The dye in the matrix transferred to the receiving sheet. For color three or
even four matrices were used. Part of the skill was keeping everything in
register. The original dye transfer process used B&W sensitized matrices
exposed to color separation negatives, usually sandwiched with masking films to
correct the color. Later, Kodak offered panchromatic matrix film which could be
used to print directly from color negative film. Of course, for making prints
from reversal films, like Kodachrome, color seps were required.
Dye transfer was superior to other methods available at the time. The prints
were sharp and had good life because the dyes could be choosen to be long
lived.
Dye transfer was popular for making originals for advertising photography
because it was relatively to retouch. Kodak offered retouching dye sets that
exactly matched the print dyes. Dye transfer was difficult but relatively much
easier than the three color carbro that it pretty much supplanted. It was also
sharper than Carbro prints, important when the print is to be photograhed to
make four color halftone plates.
Someone began to make dye transfer materials again a few years ago, I don't
know if they are still doing it. Kodak offered a lot of accessory products for
the process like pan masking film to adjust contrast and make color correction
masks.
Actually, material for carbro is available again, I think through Dick
Sullivan at Bostick and Sullivan. Carbon and Carbro are not too difficult for
monochrome but are a bear for color work. The labs that did this work in the
1930's and 1940's, when it was the standard method did nothing else.
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
Los Angeles, CA, USA
---
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